1. Field of the Invention
The present invention relates to a method of cleaning a silicon wafer and an apparatus for cleaning the same. More specifically, the present invention relates to a method of cleaning a silicon wafer, in which a water film is formed on a surface of a silicon wafer in a chamber, and then the surface of the silicon wafer is cleaned by dissolving a cleaning component of a predetermined cleaning gas into the water film. The present invention also relates to an apparatus for cleaning the silicon wafer.
2. Description of Related Art
In a variety of wafer processes, metal impurities and microparticles (particles) having a particle size of 1 μm or less are deposited on a front surface of a silicon wafer, and process damages are formed. With increasingly high integration and high functionality of semiconductor devices, it is demanded that a front surface of a semiconductor substrate be free from contamination due to metal impurities and microparticles, and that no process damage be formed. Thus, silicon wafer cleaning technology is extremely important.
An example of a conventional method of cleaning a semiconductor substrate is a “method of manufacturing a semiconductor,” as disclosed in Related Art 1. In the method, while deionized water is first continuously supplied to a front surface of a rotating silicon wafer in a single-wafer type chamber, the deionized water is contacted with anhydrous hydrogen fluoride gas, hydrochloric gas, ozone, or a mixture thereof. Thereby, cleaning components, such as anhydrous hydrogen fluoride and the like, are dissolved in the flowing deionized water, and thus the silicon wafer after being etched is cleaned.    Related Art 1: Japanese Patent Laid-open Publication No. H9-293701
In the method of cleaning the silicon wafer disclosed in Related Art 1, the deionized water as flowing water is contacted with wafer cleaning gas, such as anhydrous hydrogen fluoride gas and the like, on the front surface of the silicon wafer, as described above. Then, the cleaning components (anhydrous hydrogen fluoride and the like) in the gas are dissolved, and thus the etched silicon wafer is cleaned. The cleaning components in the cleaning gas dissolved in the deionized water is immediately discharged from the wafer front surface. As a result, cleaning effect of the cleaning components is not sufficient. Further, in the method as described above in which the water film of the flowing deionized water is used, a thickness of the water film within the wafer surface and a flow velocity of the deionized water are not stabilized. It is thus difficult to achieve an even concentration of the cleaning components within the wafer surface, and thus unevenness is caused in cleaning. The tendency has increased as a diameter of silicon wafers is larger. In addition, the cleaning components are supplied only in a gasified state.